A sawtooth voltage generator has already been proposed, in which the output voltage is picked up at a capacitor which could be charged via a first resistor of low resistance and discharged via a second resistor of higher resistance and with a longer time constant. The result is the equivalent of two RC circuits or members, in which the capacitor, i.e. the C member is the same for both circuits, but the resistors, i.e. the R members were different. The first RC circuit, upon charging the capacitor, determines the leading edge; the second, or further RC member, upon discharge of the capacitor, the trailing edge of the sawtooth voltage. This sawtooth voltage generator thus had a very steeply rising leading edge of the sawtooth voltage because of the low-resistance charging resistor, and thus the clock time was determined almost exclusively by the discharging time constant of the discharging circuit of the capacitor.